PROJECT SUMMARY/ABSTRACT Background: Evidence-based mental health (MH) treatments have great potential to reduce the burden of mental illness, but a large proportion of the US population has limited access to these treatments because insurance providers' limit the utilization of MH services at levels that are more restrictive than for physical health services. Comprehensive state mental health parity legislation (C-SMHPL) is an evidence-based policy intervention, recommended by the US Community Preventive Services Taskforce, which increases access to MH care. Uptake of C-SMHPL, however, is low. State policymakers have the exclusive authority to implement C-SMHPL, but little research exists to inform the design of strategies to disseminate evidence about C- SMHPL, and more broadly evidence-based treatments and mental illness, to this audience. Goal: This R21 application proposes an exploratory audience research study that uses a multi-level (policymaker, state), mixed method (QUAN?qual) design with the goal of improving the dissemination of evidence about C- SMHPL, evidence-based treatments, and mental illness to state policymakers. Aim 1: Characterize state policymakers' knowledge and attitudes about C-SMHPL and identify individual- and state-level attributes associated with support for C-SMHPL. A telephone-based survey of 600 US state policymakers (500 legislative, 100 administrative) will be conducted and responses will be linked to state-level variables. Survey questions will span domains such as support for C-SMHPL, knowledge and attitudes about C-SMHPL and evidence-based treatments, and measures of mental illness stigma. State-level variables will measure factors such as economic climate, political environment, and public opinion. Multi-level regression modeling will be used to determine the relative strength of individual- and state-level variables on policymaker support for C- SMHPL. Aim 2: Integrate quantitative and qualitative data to develop a conceptual framework to disseminate C-SMHPL evidence to state policymakers. Informed by Aim 1, semi-structured interviews will be conducted with a purposive sample of approximately 50 policymakers to elaborate upon quantitative findings. Then, using a systematic process, quantitative and qualitative data will be integrated and a C-SMHPL dissemination framework will be developed. Innovation: The project is innovative because it collects data from an understudied dissemination audience (i.e., state policymakers), focuses on an intervention (i.e., C-SMHPL) that has not been the focus of D&I research, and uses a multi-level design that is infrequently used in policy D&I research. Significance: The project will advance NIMH's Objective to ?Strengthen the Public Health Impact of NIMH-Supported Research? by producing knowledge that will enhance the dissemination of C- SMHPL evidence to state policymakers and therefore scale-up a policy intervention that expands access to evidence-based treatments.